Cancellation of contract

My mobile contract expired in August and I went to Telkom end of Septermber to cancel it. I submitted the cancellation form and copy of my ID to Don in the main street Branch and he said he will send it to the cancellation department.On the 5th October I went back to follow up and found that my documents were never sent. I went back on the 7 and was given a case no. ***0. My husband went there on the 18th November and was told that when I was there I changed to prepaid, I was suprised because this was not true. I called the call center and was told that the case was dispatched to the wrong department. Its the 6 Jan and my case is still not resolved and i still get billed. I have been calling the call center numerous times but no one seems to help. I demand a refund for all those months, I am sick and tired if Telkom.